Mapping Mountains – Significant Name Changes – 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales

Bryn y Gwynt (SH 599 449)

There has been a Significant Name Change to a hill that is now listed in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales, with the summit height, bwlch height, their locations, the drop, dominance and status of the hill confirmed by LIDAR analysis conducted by Aled Williams and a subsequent Trimble GeoXH 6000 survey conducted by Myrddyn Phillips and Aled Williams.

Bryn y Gwynt (SH 599 449)

The criteria for the two listings that this name change applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height with 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.

Y Trechol - The Dominant Hills of Wales - Welsh P30 hills whose prominence  equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose prominence is between one third and half that of their absolute height, with the Introduction to the Mapping Mountains publication of this list appearing on the 3^rd December 2015, and the list is now available in its entirety on Mapping Mountains in Google Doc format.

The hill is situated in the Moelwynion range of hills in the Region of North Wales (Region A, Sub-Region A1), and is positioned with the A 4085 road to its north-east and has the Welsh Highland Railway to its immediate west and overlooks the Afon Glaslyn also to its west, and has the village of Beddgelert to its north north-west and the town of Porthmadog to its south south-west.

The hill appeared in the Hills to be surveyed sub list that accompanied the main Welsh P30 lists that were published on Geoff Crowder’s v-g.me website under the name of Coed Hafod-y-llyn.  This is the name of the wood where the hill is situated and would be an appropriate name to use if a name for the hill itself did not exist.

Coed Hafod-y-llyn

56m

SH598448

124

18

Hill list authors are prone to list a hill by the name that appears nearest to its summit on contemporary Ordnance Survey maps, without much consideration for its local or historical confirmation, or whether map placement is appropriate, or as in this case whether an individual name for the hill in preference to the name of the wood it is situated in, exists.  This is not a practice I now advocate as with time and inclination place-name date can be improved by asking local people or by examining historical documents, through this form of research an appropriate name for the hill can usually be found, and in the case of this hill it was local knowledge from Aled Williams coupled with historical information from the Ordnance Survey series of Six-Inch maps that gave the name of Bryn y Gwynt for this hill.  

Extract from the series of Ordnance Survey Six-Inch maps

Therefore, the name this hill is now listed by in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales is Bryn y Gwynt and this was derived from local enquiry and the Ordnance Survey series of Six-Inch maps.

The full details for the hill are:

Group:  Moelwynion

Name:  Bryn y Gwynt

Previously Listed Name:  Coed Hafod-y-llyn

Summit Height:  59.9m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SH 59949 44919 (Trimble GeoXH 6000) 

  

Bwlch Height:  28.0m (LIDAR)

Bwlch Grid Reference:  SH 60224 45248 & SH 60226 45258 & SH 60227 45259 (LIDAR)

Drop:  31.9m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  53.21% (Trimble GeoXH 6000 summit and LIDAR bwlch)  

My thanks to Aled Williams for sending the details of this hill to me.

Myrddyn Phillips (February 2018)